First, the frame structure of a wireless communication system will be described with reference to FIG. 1. FIG. 1 is a diagram showing a frame structure of a Long Term Evolution (LTE) system. As shown in FIG. 1, one frame includes 10 subframes and one subframe includes two slots. A time consumed for transmitting one subframe is referred to as a Transmission Time Interval (TTI). For example, one subframe may have a TTI of 1 ms and one slot may have a TTI of 0.5 ms.
One slot includes a plurality of Orthogonal Frequency Division Multiplexing (OFDM) symbols. The OFDM symbol may be also called an OFDMA symbol, a Single Carrier-FDMA (SC-FDMA) symbol, or a symbol interval.
One slot includes 6 or 7 OFDM symbols according to the length of a Cyclic Prefix (CP). The LTE system includes a normal CP and an extended CP. In the case of using the normal CP, one slot includes 7 OFDM symbols and, in the case of using the extended CP, one slot includes six OFDM symbols. The extended CP is used when delay spread is wide.
A mobile station may transmit uplink control information through a Physical Uplink Control Channel (PUCCH). The uplink control information may include a variety of information such as a Scheduling Request (SR), an Acknowledgement/Non-Acknowledgement (ACK/NACK) signal, a Channel Quality Indicator (CQI), a Precoding Matrix Indicator (PMI) and a Rank Indicator (RI). The PUCCH is used to carry a variety of control information according to formats.
There is a need for a method for efficiently transmitting a variety of uplink control information.